


whip the blankets

by nilchance



Series: ain't this the life [23]
Category: Undertale (Video Game)
Genre: Anal Sex, M/M, Rimming, Underfell Sans (Undertale), eventual spicykustard, kustard - Freeform, offscreen fellcest
Language: English
Status: Completed
Published: 2019-04-11
Updated: 2019-04-11
Packaged: 2020-01-11 21:49:23
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 6,073
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18432773
Author URL: https://archiveofourown.org/users/nilchance/pseuds/nilchance
Summary: Sans tests some hypotheses and pushes his luck.





	whip the blankets

**Author's Note:**

> detailed content warnings in the endnotes

Edge blushed.

Sans stares at the door to the embassy that Edge disappeared through, not really seeing it. He’s too busy rubbing at the unfamiliar weight of the collar around his wrist and remembering the expression on Edge’s face just before he beat a hasty retreat. If they hadn’t been in the daylight, Sans probably wouldn’t have seen the very faint pink brushed across Edge’s sharp cheekbones.

He has feelings about that blush. A lot of feelings that he can’t confuse with the ones he has for his brother no matter how much he prods at that mental comparison like a bruise, waiting for the moment that he finally comes to his senses and freaks out. But that moment didn’t come, even when he flirted, even when he suggested a friendly totally-not-a-date, even when Edge gave him that strange, searing, _wanting_ look like he wanted to bend Sans over the bench and--

So. Yeah. The experiments so far have been a success. The tentative hypothesis of ”maybe I want to smooch Edge tenderly on the face while riding him through the mattress” is being confirmed. He’s not done testing, not yet, but the fact is that there’s a sweet, fragile light in his soul with each experiment he runs that he can’t pretend isn’t happening.

Well, he could. But that whole denial thing isn’t working out so great for him these days. He’s got to reserve it for special occasions. Besides, at the moment, he’s got something else to worry about.

All that talk of Red’s job as superspy has put an uncomfortable suspicion in Sans’s mind, one that really should’ve occurred to him way before now. He reaches beneath the bench, feeling along the underside, and finds only calcified gum. Gross, but not helpful.

He gets up, circling the bench, examining the back. Nothing. It isn’t until he feels under the arm rest at the left side of the bench that he finds it, a little bump of plastic and metal. It pulls off relatively easily, and he’s left staring at a nifty little recording device.

He should’ve seen this coming. It’s not like he hasn’t discovered the occasional one of these in his own house, tucked in a kitchen cabinet or underneath the couch. He already told Red he’d feed him the next bug he found in Papyrus’s room. And he and Edge have been using this same bench for the last couple months. It must’ve been too rich a source of information for Red to resist, if he even tried resisting the temptation at all.

“Hey, Red,” Sans says into the bug’s microphone. “Putting the brother in Big Brother, huh? This is kinda creepy even for you.”

There’s a long moment where nothing happens, long enough for Sans to start to wonder if he just made some poor CIA agent listen to him flirt badly for the last twenty minutes. Then from behind him comes Red’s voice. “Creepy is an ugly word. I prefer thorough.”

Sans turns around. Red is there, hands in his pockets, grinning a grin that tells even Sans pretty much nothing. He looks tired, but it’s probably just because he blew through too much magic yesterday. Something to keep an eye on, though.

Sans flicks the bug at him, and it bounces off Red’s sternum. Red catches it on the rebound. “Thoroughly something. Do I pass the job interview?”

There’s no warning. In a few smooth steps, Red gets into his space, grabs him by the front of his jacket, and hauls him close, forcing Sans up onto his toes. Sans feels heat roll over him in a flashburn, annoyance and desire and a tinge of fear tangled up into one delicious thing.

From a distance, it probably looks like either a mugging or an overly handsy couple riding the line between PDA and an exhibitionist kink. From where Sans is standing, it kinda feels like Red dragging him closer to get the best angle from which to shank him. That probably should kill his boner, but nope, he is unfortunately into it.

“You already cashed that blank check,” Sans says, trying to sound bored but mostly ending up a little breathless. “Sorry, pal. Anything else is gonna bounce. My account’s in the, heh, red.”

“Are you screwing with him on purpose, sweetheart?” Red asks, not a trace of humor in his expression. “Because there’s a big difference between you fucking my brother and you fucking with his head.”

So that’s what this is about. It’s too fair a point for Sans not to wince. He gets the feeling he better pick his next words very carefully. It’s no small thing for Red to trust Sans enough to let him fuck Edge. It was probably because he thought Sans was too weak to do any harm at first, but he hasn’t withdrawn the offer now that he knows how Sans killed their king. Red doesn’t trust easily, and if Sans screws that up, he’s not getting it back.

Unresisting in Red’s grip, Sans says, “I wouldn’t do that to him.”

Red searches his face. It’s not a cold, distant look. Red knows him now, knows how he ticks, and it’s with that intimacy that Red disassembles him, considers every part, and judges whether or not it’ll run. Sans holds his eyes. After a moment, Red’s grip relaxes. He asks, “Then what’re you doing?”

Sans laughs. It’s sharp. “I have no fucking idea. I’m fumbling around in the dark here trying to find the light switch, and I don’t know if the power’s been cut off even if I do find the damn thing.”

That metaphor is so tortured it probably counts as a war crime, but it seems to do the trick. With a snort, Red lets him go entirely and takes half a step back to give him space. Sans pretends he’s not a little disappointed. “At least you finally figured out there _is_ a fucking light switch. I was laying odds on it being another couple years.”

“Buddy, you have more faith in me than I deserve.” Sans should probably reclaim his personal space, but it seems like too much trouble. He’s not going to give Red the satisfaction of him being the one to move. “Should’ve given it at least five.”

“You’d have gotten it one way or the other. If you hadn’t figured it out by December, I was gonna break out flash cards,” Red says. “Y’know, you could always just fuck him.”

“Sure. No big deal, just me fucking him and you and whoever else I want on the side,” Sans says. “You think he’d be satisfied with that?”

“Heh.” Red’s grin is briefly sharp as a razor, the kind of sharp where you don’t even feel the cut. “Sweet of you to think of what satisfies him, Sansy.”

There are undercurrents beneath that comment that would take Sans’s legs out from under him if he lets them. He thinks of the mark on his collarbone, the feral shine in Red’s eyes when he nuzzled the collar around Sans’s wrist. All the quiet things Red has been doing to stake a claim since Sans got back from his universe. 

Unfamiliar territory. Maybe he could map it out, though. If he stuck around long enough. If he wanted to.

Sans says, “Y’know, an obnoxious philosopher once told me that if you want something, maybe you should actually ask for it.”

Red gives him a slow blink like a cat deciding whether it’s worth leaving this comfortable sunbeam to terrorize a mouse. Then his grin goes crooked. “He’s a territorial bastard.”

“Apparently,” Sans says dryly.

“The boss, I mean,” Red says. “Question is would it be enough for you?”

Boy, it’d be great if Sans had an answer for that. He gives a helpless shrug. “Dunno. That’s what I’m trying to figure out.”

“Huh,” Red says. Idly, in that way that’s not actually idle at all, he takes Sans’s wrist. The collar is buried safely out of sight and reach, but Sans is suddenly very aware of it, like it’s responding to Red even through the jacket. He’s ignorant enough of how this whole thing works that he can’t swear that’s not exactly what it’s doing. Fuck knows what would happen if Edge touched it. “All right. So a little flirting here, a trip to the movies to hold hands or whatever sappy bullshit there, and if you can’t take it, hey, plausible deniability. No harm, no foul.”

“It’d be kinda awkward if I said I wanted to fuck him and realized as soon as he got his pants off that he reminds me too much of Papyrus and I need to bleach the inside of my skull,” Sans says.

“Sounds hot,” Red says, grinning.

Sans grimaces. “I’m gonna pretend you’re talking about some heretofore unknown bleach kink for my own peace of mind.”

“You pretend a lot of things for your own peace of mind, Sansy,” Red says. “But all right. Do what you gotta do to figure it out. You got my blessing.”

“It’s so reassuring to know that you won’t greet me on the porch with a shotgun and demand to know my intentions towards your brother,” Sans says.

“Pretty sure I already know your intentions, sweetheart,” Red says. “See, I think you figured out what you want the second you put that collar on and the rest of this is you thinking you ain’t allowed to have it.”

Sans’s soul gives a hard double-thump behind his ribs like it’s the telltale heart under the floorboards, reminding him of his mistakes. It doesn’t quite hurt, but considering his soul has more or less behaved itself since Edge last healed him, it’s unnerving. Sans pulls his hand out of Red’s grip to rub at it through his jacket. That’s a glaring tell, but it’s nothing Red doesn’t already know.

“Technically, you’re the one who put the collar on,” Sans says.

“Works better if somebody else puts it on for you. I’m a helpful guy.” Sans snorts and Red’s grin briefly widens. Then, all business, he asks, “Soul acting up again?”

“Some.” Sans shrugs. “It’s not bad.”

“Hurts?” Red asks. 

When Sans shakes his head, Red reaches out and puts one hand on the back of Sans’s neck. It’s weird to have him do that in broad daylight, in the open, the two of them standing intimately close where anyone could see. He doesn’t protest even though he probably should.

“Gonna need another fix pretty soon,” Red says, stroking Sans’s spine with his thumb. “You’re colder than you were yesterday.”

“We’re dealing with that tomorrow night. I can take it ‘til then. And I figured you were a little busy getting your rocks off to take my temperature,” Sans says.

“What, you’re not down for playing a little doctor?” Red asks. 

Sans thinks he keeps his expression under control, but he wasn’t braced for that one, and Red immediately loses the playful look. His eyes narrow.

Sans shrugs his hand off and decides to take those steps backwards to reclaim his space after all. “Nah, that’s okay, Dr. Feelgood. Latex gloves don’t really do it for me. Unless you make balloon animals with ‘em because fuck, that’s an instant boner right there.”

“I don’t need help to give you an instant boner,” Red says, still eyeing him thoughtfully.

“Yeah, I got 206 of them,” Sans says. “Are you done trying to menace me for Edge’s honor? Because I’m starving.”

“That’s fucking rich coming from you, but nah, we’re good,” Red says. “Just so you know, you caught him off guard just now, but you keep fumbling around for that lightswitch and he’s gonna figure it out. Maybe ease up on the flirting. Little friendly advice.”

“Yeah, I know.” Sans rubs at his brow and the gathering headache there. Red has that effect on him. “This shouldn’t take long.”

“Better not. I’m gonna die of blue balls.” Red snags Sans by the front of his jacket and starts pulling him towards the park exit, where there are a couple cabs idling. Sans immediately and deliberately goes three times slower than he was going to just to be a dick. Walking backwards like a man with ridiculous spatial awareness and the conviction that he’s the scariest motherfucker in the vicinity, Red says, “S’okay, babe. You go on your little date. It’s adorable. You can share popcorn or whatever normal people do, if pretending like you’re normal gets you off. Or you can give him a handjob in the theater. I vote for that one.”

“You’re the reason why theater floors are sticky, aren’t you,” Sans says. “Just you personally, going from town to town, baptizing the floors in jizz.”

“A guy’s gotta have a hobby,” Red says. “Tell you what. Since you’re famished, we’ll go to my place. Order some takeout from that sushi joint a couple blocks away. Then we’ll see what we can do to keep that motor of yours purring until tomorrow, since you’re a fucking sex vampire and all.”

(Funny how their regular itinerary seems different with the addition of a little food delivery. Like if Sans got a head injury and then squinted really hard, it could be their extremely low-commitment, no pressure, no fucks given version of a date.)

“Sex vampire is redundant,” Sans says, drowning out that thought with words. Any words will do. He’ll go off on a soliloquy about nothing if it keeps him from having to associate Red with the concept of dating as a whole. “Those filmy nightgowns and slow-mo shots of throats getting penetrated while people make orgasm faces? All those shots of fluids running out of people’s mouths? Humans knew what they were doing, the horny bastards.”

“Maybe you just have a dirty mind,” Red says.

The audacity of that statement coming from Red of all people leaves Sans staring at him for a moment. Then he says simply, “Wow.”

“Hey, I used to be such a sweet, sweet thing before you got a hold of me,” Red says.

“Now you’re just quoting Alice Cooper _and_ lying through your teeth. Real nice.” Despite Sans’s dawdling, they’ve finally reached the taxi queue. Sans swats Red’s hand away. “You’re paying for the cab fare.”

“I’ll buy you dinner too if you put out,” Red says, his eyes half-lidded and his grin a challenge.

That’s… a thing. Culturally speaking. That is definitely a thing Sans heard right there. He is frozen in the headlights of that oncoming thing.

Well, he told Red to ask for what he wanted.

“No thanks,” Sans says, trying to sound like totally missed any subtext whatsoever. It shouldn’t be hard, considering how goddamn much he’s missed up until now. He clears his throat. “Uh, ask me again next time, maybe. Besides, I always put out.”

“Aw, I’ll be sure to tell the boss,” Red says, looking totally unoffended. He’s not gonna get weird about it. Weirder, anyway. That’s a relief. “He’ll be stoked. Are you getting in the fucking cab or what?”

It’s been a long, weird afternoon. Sans gets in the fucking cab.

***

Over the process of an hour or so, they destroy the takeout. Red “accidentally” leaves out some chunks of raw fish on a saucer on the kitchen counter, like Sans didn’t watch Red meticulously dissemble some poor unsuspecting sashimi as Doomfanger stared and licked his chops. Then they leave Doomfanger snarfling his ill-gotten gains and retire to Red’s bedroom so Sans can climb on Red, pin his shoulders to the mattress and make out with him for a long, luxurious while. There’s no hurry. Sans has nowhere to be.

Red is warm and surprisingly pliant beneath him, although Sans doesn’t doubt that Red could be on his feet and killing something in seconds if he had to. His hands roam Sans’s back, kneading his hips, sometimes gripping the middle of his spine and thumbing the vertebrae. He’s breathing heavily, the heat of his magic rubbing against Sans when he grinds down on Red’s pelvis, and Red’s going to be the one to ask for more if Sans has to drag it out of him.

Sans always knew he had a mean streak. But nobody brings it out in him like Red. It’s a power trip to make Red desperate for him, to make him be the one to give it up. Maybe Sans should worry about that, but he’s drunk on sensation and the little noises Red makes into his mouth as Sans rides him through their clothes.

When Sans pulls away from Red’s mouth, shifting so he can get at Red’s cervical vertebrae and just so happening to viciously grind on Red’s pelvis at the same time, Red folds like a stack of cards. His voice is rough. “Honey, we gotta move this along unless you want me to come in my pants like a fucking teenager.”

The idea has its appeal. But Sans climbs off him, taking a moment to admire his handiwork. Red’s all rumpled and sweaty and his pupils are blown. Sans can see his magic glowing faintly through his shorts. He looks thoroughly debauched. Never mind that Sans isn’t much better off.

Red lays his hands beside his head, mimicry of him holding Sans down by his wrists last time. Sans’s breath catches traitorously in his throat, and Red’s grin sharpens. “Your turn behind the wheel. You were so damn sweet last night--”

“Dude,” Sans says flatly.

“So I figure I should return the favor. What’s your pleasure?”

“Right now? Calling a cab and leaving you to enjoy your blue balls.”

Red snorts, not buying that for a second, which Sans probably deserves. He reaches out and palms Red’s magic through his shorts. It’s shapeless, just roiling heat under his fingers. Red groans low in his throat, tilting his hips up into Sans’s touch, and then curses when Sans pulls his hand away. Casually, like he doesn’t give a fuck, Sans says, “You said I could have your ass anytime I wanted. That still on the table?”

“Heh. Yeah, I mighta said that,” Red says. “Figured I played with yours so you oughta play with mine?”

“You opened the back door to a whole new world of possibility,” Sans says. Red snickers, and Sans hooks a thumb under the waistband of his shorts to release it with a snap. “Take these off and roll over.”

“Hell yes,” Red says, already peeling out of his clothes. Tossing them to the side, he turns over onto his front, making himself comfortable, his head on his folded arms. “Just fuck me up.”

Zero shame, one hundred percent enthusiasm. Sans feels a bright, dangerous stab of fondness for him. He runs his hand down the curve of Red’s spine, which is less scarred than the rest of him but still has a few chips and scratches where somebody probably attacked him from behind.

(And yet here he is, giving Sans his back without any hesitation.)

“Weird. The only ass I see here is you,” Sans says.

Red grins at Sans over his shoulder. “What, now you’re in a rush?”

Between one blink and the next, Red’s got magic from the bottom of his ribs to the top of his knees. It’s a ridiculously extravagant use of magic, especially after Red blew so much of his energy yesterday on those tentacles, but maybe that’s what his extra four HP and practice getting fucked has gotten him.

Tragically, Red was right about his ass. It’s probably one of the best asses Sans has ever seen, and he’s got a good sample size to work from. Sans has never given a lot of thought to what he looks like naked, mostly living in his head and riding his body around like a weird bone mecha because he learned a long time ago that helped manage the pain, but seeing it on someone else, he’s maybe understanding some of Red’s narcissism.

“You looking for your car keys or something?” Red drawls. “I’m getting bore--”

Sans grabs him by the hips and hauls him up onto his knees. Red is surprisingly easy to move, especially since after a startled moment he seems to catch Sans’s drift, shifting his legs further apart. When Sans fills his hands with warm, lush magic, using his thumbs to spread Red open, Red laughs, a disbelieving, delighted sound that chokes off into a moan as Sans bends down and drags his tongue up the cleft of his ass, getting it wet.

“Oh,” Red says, muffled into the mattress. When Sans presses the tip of his tongue against the tight furl of Red’s asshole, pushing in a little, Red sounds halfway delirious. “Oh, sweetheart, your fucking mouth.”

It’s nice to be appreciated. Sans hums against him, acknowledging that yes, he’s pretty good with his mouth, and Red jerks. Not very cooperative of him, but then Sans has no idea how this feels from the other end of things. People certainly seem to lose their minds over it.

Kneading Red’s ass, Sans keeps at it as Red’s noises get increasingly raw and frantic. He’s tight and twitching beneath Sans’s tongue, but slowly he yields and opens up. After a minute (or maybe a few, or five, or ten; it’s hard to keep track of time when he’s focused on what he’s doing like this, he’s barely keeping track of the need to breathe) Red starts rocking back a little against his mouth. Sans could make him stop. He doesn’t.

He can smell the wetness of precum thick and sweet in the humid air of the bedroom. He spares a hand to reach between Red’s spread thighs, finding his dick. It’s heavy and hot in his hand, slick beneath his fingers. Red pushes into his hand and says raggedly, “Fuck, yeah, touch me.”

The desperation in Red’s voice, brought on that easily, makes slow heat roll down Sans’s spine. He is suddenly and brutally aware of the fact that his own dick is pressed throbbing and neglected against his shorts. He didn’t even get his fucking clothes off. He doesn’t stop, his mouth ruthless even as he keeps the touch of his hand light, feeling Red out with his fingertips. Red’s legs tremble like they’re going to buckle, his noises nearly agonized.

When Sans reaches the head of his dick, rubbing his thumb over the slit, Red breaks. He thrusts forward into the loose circle of Sans’s fingers, fucking his hand as he comes in hot spurts. Sans pulls back to heave in a breath (and so he doesn’t get whiplash in the worst way possible) and tightens his grip a little to give Red something more satisfying to work with. It sounds like Red appreciates it, at least.

After about a minute, Red’s thrusts grind to a stop. The arch of his spine is weirdly graceful, his ribs rising and falling as he tries to catch his breath. Sans pats his hip and says, “So you want a juice box? I got fruit punch or blue raspberry.”

Red snorts, then stretches long like a satisfied cat. “We ain’t done. Last time you said you’d fuck me.”

Sans’s dick is a big fan of that idea, which makes it a little hard to sound cool and unconcerned when he says, “You got lube?”

It’s not the kind of thing Sans carries around, but Red strikes him as a guy who has lube in pretty much every room of his house just in case.

Red gives him a look over his shoulder. “This isn’t my first rodeo. You can skip that part.”

“Not what I asked,” Sans says.

They stare at each other. After a minute, Red scoffs, pulls a half-empty plastic bottle out of his inventory, and tosses it at him. “Fine. Make like I’m some vanilla human fuckboy and it’s my first time getting pegged. See if I care.”

“Weird roleplay, but whatever gets you off.” Sans slicks his fingers with what seems like a reasonable amount of lube and adds about double that just to be on the safe side. Then he slides one finger in, and Red’s breath hitches softly. Despite his bullshit, he’s tight enough that just shoving into him wouldn’t do either of them any favors. Friction burn on his dick isn’t Sans’s idea of a good time. But then again, maybe Red’s into that kind of pain. Fucking him slow, Sans says, “Don’t worry, baby. It doesn’t make you gay.”

Snickering, Red puts his head back down on his arms. If it bothers him to be in this position, ass up in the air, he doesn’t show it. His body is relaxed, almost languid, which is probably because Red’s the lucky bastard who already got off. 

When Sans slips a second finger into him, a shiver runs through Red’s body, which turns into a harder shudder when Sans angles his fingers to reach his prostate. Another thing Sans has no point of reference for, although he knows it can be hit or miss for people. He asks, “That work for you?”

Red hums his approval, then shifts his weight on his knees, lazily fucking himself on Sans’s fingers in a shameless way that goes straight to Sans’s dick. Sans adds a third finger, drinking in Red’s groan of appreciation and sheer want. It’s satisfying to see Red like this, on his knees and loving it.

“C’mon, I’m good for it,” Red says after less than ten seconds, mingled frustration and amusement.

There’s a hot, spiteful part of him that wants to make Red beg for it only to deny him. But he can feel that Red’s eased up around his fingers, and he’s not actively trying to be a dick here. He’s not Red.

“Since you asked so nicely,” Sans says.

He makes sure to be a little rough pulling out his fingers and Red twitches, his dick hard again between his legs. Wiping the lube off on the back of Red’s thigh, earning himself an amused snort, Sans finally shoves his own shorts down and out of the way. He doesn’t bother taking off his shirt, just coats his dick with more lube despite the fact that it’s already pretty slick with precome. The coolness of it makes him hiss.

As Sans lines himself up, Red says, “About time you--”

Sans grabs Red’s hips and pulls him back onto his dick. Red chokes on whatever he was going to say, his spine arching at an angle that looks painful as he gasps out, “Fuck, Sans,” in a tone that sounds like anything but pain.

Of course, Sans kind of fucked himself over with that maneuver. Even with all the warm-up, Red is _tight_ , an incredible amount of sensory input all at once. He has to hold himself still for a moment to try not to embarrass himself like a fucking teenager, clinging to control with his fingertips until the urge to just use Red to get off fades to something bearable. 

His fingers are digging hard into Red’s hips. When he forces himself to ease up, there are marks left behind, darker splotches on his magic. Red makes a disappointed little noise that turns into a heartfelt moan when Sans tentatively thumbs one of the bruises.

Sans hesitates. Then he reaches out, rests his hand on the back of Red’s neck, and pushes Red’s head down against the mattress. He can feel Edge’s magic in the collar, a faint resonance in his head like Edge is a ghost in the room, watching, a thought that makes him tremble. Sans isn’t putting much pressure on, but Red shudders hard, tightening around him, and groans, “Oh fuck yes.” 

Acceptance. Surrender. It hits Sans like his first reckless hit off a joint, the sudden dizzying flood of it making his head swim. Then there’s a second, softer wave of tenderness for the dangerous bastard who’s just letting Sans hold him down. Red could break his grip (along with every bone in Sans’s body) if he wanted to, but he takes it.

Soul pounding heavily in his chest, Sans asks, his voice unsteady, “Is that what you wanted?”

“Yeah,” Red says, softer but no less emphatic. His hips twitch, trying to move back into Sans, and Sans tightens his grip. Not enough to hurt, he hasn’t lost his mind enough to forget the terms and conditions Edge placed on this whole arrangement a few months ago, but enough to make a point. Red makes a noise that goes straight to Sans’s dick, almost a laugh, and stops fighting.

(He’s just going this far because it’s what Red wants. He’s just--)

Sans’s hands are shaking with adrenaline and a kind of wild joy. He strokes Red’s spine with his thumb and rocks into him, testing the waters. He’s not going to be able to drag this out long. There’s already that tight feeling at the base of his spine, building as he thrusts again and hears the deep, grateful sound Red makes. 

But Red seems to be right there with him, clawing the mattress, trembling like he’s feverish as Sans starts to fuck him with more purpose. He’s talking because nothing can actually shut Red up for longer than about fifteen seconds at a time, but it’s not exactly coherent, just a litany of praise and variations of the words _fuck_ and _yes_ that almost manages to drown out the sounds of Sans fucking him.

“Jerk yourself off,” Sans pants, barely keeping control through a combination of pride and sheer spite. He hears and feels more than sees when Red obeys, the volume of Red’s moans ratcheting suddenly up as he tightens down on Sans hard enough that Sans sees stars. 

His control slips through his fingers. In a fever, he takes what Red is offering, driving into him hard and fast. Red cries out every time he strikes home, louder each time. It’s rough and graceless and _good_.

He thinks Red comes first, but it’s a close enough thing not to really matter, the two of them lost in it together. It leaves him weak in the aftermath, trembling as he leans over Red’s back, his forehead pressed to Red’s shoulder, and tries to breathe. Red seems no better, practically limp beneath him, and Sans would be more worried if Red wasn’t still blearily mumbling semi-coherent bullshit into the mattress.

Which Sans is sort of pushing his face into. Fuck. He takes his hand off Red’s nape and straightens up, and Red growls a complaint and paws ineffectually at him with a jizz-sticky hand. Sans says, “I’m not going anywhere. Just gimme a second.”

Grumbling, Red subsides.

Sans pulls out, his dick giving a twinge of overstimulation. A little trail of blue starts to trickle out of Red, winding its way down Red’s thigh. Sans draws in a breath, suckerpunched, and gives in to the visceral urge to gather up that come with a fingertip and push it back in. Red’s breath shudders out, and he shifts his unsteady legs further apart, offering himself up.

Fuck, Red is hard on Sans’s good intentions. As hard as he wrecked Sans yesterday, Sans deserves to get a little of his own back. It’s tempting to just slide back into him while he’s all boneless (ha) and unresisting, or maybe eat him out for a while and see how loud he gets when he comes again. As it is, it’s a good thing they don’t have neighbors. Sans made good on that promise to make Red scream.

Instead, Sans firmly dismisses his magic and gives Red’s ass a last affectionate pat. Then, gently, he tips Red over onto his side. Red grins sleepily at him, streaked with his own come, blue between his thighs, and goddamnit, this is not doing anything for Sans’s restraint. Red sighs, “Fuck, sweetheart, you’re too good to me.”

Some knot of tension in Sans’s soul eases up. Red was giving him green lights all the way, but still. They should’ve talked about it or something. “You want that juicebox?” 

“Hell yeah. The blue one.” Red yawns. “If I ask nice, will you put me over your knee?”

“Edge might have a few things to say about that, so no,” Sans says. Then he catches the delight in Red’s eyes, recognizes that was the wrong thing to object to, and adds, “And it’s not my thing.”

“Whatever you say, babe,” Red drawls. “Kinda hard to believe when you just pushed my face into the bed while we were screwing, but hey, who am I to judge?”

Deciding to ignore that, Sans lets himself be pulled down and submits to Red wrapping himself around him like an octopus. It’s weird to feel a warm, soft stomach and thighs pressed against him instead of just bone. He tells Red, “Quit showing off or you’re gonna end up crashing on the couch for a four hour nap again.”

Red makes a dismissive noise, but a moment later, his magic is gone. It gives him more room to snuggle closer, which he does. “I just hired this new guy. He’ll cover for me.”

“Interesting interviewing process you’ve got there,” Sans says, pulling the juice box out of his inventory. When he tries to pass it to Red, he doesn’t move. Sans sighs. “I’m not putting the straw in for you, dude.”

Nuzzling against his shoulder, Red says, “Came too hard. Can’t feel my fingers.”

“That sounds like a you problem.” Red still doesn’t move. “If I’m gonna do that, I need my arm back.”

“You’ll figure it out,” Red says.

Sans doesn’t know what else he expected. He has no one to blame for this but himself. 

Unwrapping the straw and getting it in the stupid little straw hole is a whole process one-handed, but that almost-doctorate comes in handy. When it’s done, he balances it on the side of Red’s face. Red grins, his eyes still closed, looking almost… content.

“Enjoy your stupid juicebox, asshole,” Sans says. It comes out fonder than he means it to, especially considering that he kind of wants to shove Red’s insufferable face back in the bed and try to smother him.

Red picks the juicebox up, sticks the straw between his teeth, and drinks. Then he sighs happily. “Ahh, tastes like you being my bitch.”

“Bold words from somebody I just fucked up the ass, but okay.” Sans pets Red’s hip, lifting his head to double-check that he didn’t leave any marks there. Looks like he didn’t grip hard enough to bruise actual bone. Good. He lets his head drop back to the mattress, listening to the rhythm of Red’s breathing. He should probably try to extricate himself and make an escape, or at least pretend to try, but instead he says, “You wanna move this to the couch?”

His answer is the godawful noise of Red emptying the juicebox and continuing to suck. After several unpleasant seconds, Red crumples the juicebox and tosses it into a distant corner of the room, then belches. When he raises an expectant brow at Sans, Sans’s verdict is, “Maybe an eight out of ten.”

“Hey, that was at least a nine,” Red says, offended. “I coulda burped most of the alphabet with that one.”

“Most,” Sans says. “It’s like horseshoes and hand grenades.”

“You’re breaking my heart, Sansy.” Red rubs his face on Sans’s shoulder, closing his eyes. His fingers curl back around Sans’s wrist, thumb stroking the leather of the collar. “Couple more minutes. Then couch. Cool?”

There’s a strange note to the question that makes Sans reconsider the dark circles under Red’s eyes. Not just fatigue from overusing his magic, then. Which isn’t exactly surprising. Considering the clusterfuck of the last few weeks, it’s kind of amazing Red held it together as well as he did. Hopefully this round won’t end with Red accosting him in any alleys. 

(In the unpleasant way, anyway.)

“Cool,” Sans echoes. He starts petting Red’s ribs, long easy strokes, and Red melts into him by slow degrees. He has the feeling that it might be longer than a couple minutes before Red’s ready to go anywhere. The arm trapped under Red’s head is already falling asleep. He settles into the mattress, getting as comfortable as he can be. “No rush. I’m on company time.”

Red laughs.

**Author's Note:**

> Content warnings: Red eavesdropping on all his loved ones like a creeper to show his affection, Red menacing Sans when he suspects that Sans is deliberately screwing with Edge's head, Sans having a bad Gaster-related moment, undernegotiated kinky bullshit (which turns into enthusiastic consent)


End file.
